Hybrid aircraft propulsion system with remotely located electric machine

Abstract

An aircraft system is provided that includes a propulsor rotor, a geartrain, a thermal engine, a drivetrain and an electric machine. The geartrain includes a power output, a first power input and a second power input. The power output is coupled to the propulsor rotor. The thermal engine is configured to drive rotation of the propulsor rotor through the geartrain. The thermal engine is coupled to the first power input. The drivetrain includes a first driveshaft and a second driveshaft. The first driveshaft is coupled to and between the second power input and the second driveshaft. The second driveshaft is angularly offset from the first driveshaft. The electric machine is configured to drive rotation of the propulsor rotor through the drivetrain and the geartrain. The second driveshaft is coupled to and between the first driveshaft and the electric machine.

What is claimed is: 
     
         1 . An aircraft system, comprising:
 a propulsor rotor;   a geartrain including a power output, a first power input and a second power input, the power output coupled to the propulsor rotor;   a thermal engine configured to drive rotation of the propulsor rotor through the geartrain, the thermal engine coupled to the first power input;   a drivetrain including a first driveshaft and a second driveshaft, the first driveshaft coupled to and between the second power input and the second driveshaft, and the second driveshaft angularly offset from the first driveshaft; and   an electric machine configured to drive rotation of the propulsor rotor through the drivetrain and the geartrain, the second driveshaft coupled to and between the first driveshaft and the electric machine.   
     
     
         2 . The aircraft system of  claim 1 , wherein the second driveshaft is angularly offset from the first driveshaft by an acute angle. 
     
     
         3 . The aircraft system of  claim 1 , wherein the second driveshaft is angularly offset from the first driveshaft by a right angle. 
     
     
         4 . The aircraft system of  claim 1 , wherein the drivetrain further includes an angle drive coupled to and between the first driveshaft and the second driveshaft. 
     
     
         5 . The aircraft system of  claim 1 , wherein
 the propulsor rotor is rotatable about a rotational axis; and   the thermal engine is located axially between the geartrain and the electric machine along the rotational axis.   
     
     
         6 . The aircraft system of  claim 1 , further comprising:
 an airframe structure;   the thermal engine and the electric machine independently mounted to the airframe structure.   
     
     
         7 . The aircraft system of  claim 6 , wherein the airframe structure is configured as an aircraft wing. 
     
     
         8 . The aircraft system of  claim 7 , wherein the electric machine is housed within the aircraft wing at a leading edge of the aircraft wing. 
     
     
         9 . The aircraft system of  claim 6 , wherein
 the thermal engine is disposed outside of the airframe structure; and   the electric machine is at least partially housed within the airframe structure.   
     
     
         10 . The aircraft system of  claim 6 , wherein the electric machine is vertically below the airframe structure. 
     
     
         11 . The aircraft system of  claim 6 , wherein the electric machine is outside of the airframe structure. 
     
     
         12 . The aircraft system of  claim 6 , further comprising a nacelle at least partially housing the thermal engine and the electric machine. 
     
     
         13 . The aircraft system of  claim 1 , wherein
 the thermal engine includes an exhaust duct at an aft end of the thermal engine; and   at least a portion of the electric machine is disposed aft of the exhaust duct.   
     
     
         14 . The aircraft system of  claim 1 , wherein
 the electric machine is configurable as an electric motor during a motor mode of operation to drive rotation of the propulsor rotor through the drivetrain and the geartrain; and   the electric machine is further configurable as an electric generator during a generator mode of operation where the thermal engine is configured to power the electric machine through the geartrain and the drivetrain.   
     
     
         15 . The aircraft system of  claim 1 , wherein the thermal engine is configured as a gas turbine engine. 
     
     
         16 . The aircraft system of  claim 1 , wherein the propulsor rotor comprises a propeller rotor. 
     
     
         17 . An aircraft system, comprising:
 a propulsor rotor;   a thermal engine configured to drive rotation of the propulsor rotor;   an electric machine configured to drive rotation of the propulsor rotor; and   an aircraft wing, the thermal engine and the electric machine independently mounted to the aircraft wing.   
     
     
         18 . The aircraft system of  claim 17 , wherein
 the thermal engine is disposed outside of the aircraft wing; and   the electric machine is at least partially housed within the aircraft wing.   
     
     
         19 . The aircraft system of  claim 17 , further comprising:
 a geartrain including a power output, a first power input and a second power input, the power output coupled to the propulsor rotor, and the first power input coupled to the thermal engine; and   a drivetrain including a first driveshaft, a second driveshaft and an angle drive coupling the first driveshaft to the second driveshaft, the first driveshaft coupled to the second power input, the second driveshaft coupled to the electric machine.   
     
     
         20 . An aircraft system, comprising:
 a propulsor rotor,   a thermal engine configured to drive rotation of the propulsor rotor;   an electric machine configured to drive rotation of the propulsor rotor; and   an aircraft wing, the thermal engine disposed outside of the aircraft wing, and the electric machine at least partially housed within the aircraft wing.